One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,7,5)(3,4,8,6)(9,10)(11,14)(12,21)(13,17)(15,18)(16,20)(19,24)(22,23)(25,26)(27,31)(28,32)(29,37)(30,34)(33,39)(35,36)(38,40)(2,5)(3,8)(9,11)(10,14)(12,13)(15,19)(16,22)(17,21)(18,24)(20,23)(25,27)(26,31)(28,34)(29,35)(30,32)(33,40)(36,37)(38,39) involution — undirected(1,3)(2,6)(4,5)(7,8)(11,19)(12,20)(14,24)(16,21)(25,27,30,32)(26,28,34,31)(29,38,39,35)(33,40,37,36)(1,4,7,6)(2,3,5,8)(9,12)(10,16)(11,13)(14,22)(15,20)(17,24)(18,21)(19,23)(25,27)(26,28)(29,35)(30,32)(31,34)(33,36)(37,40)(38,39)(1,5,7,2)(3,4,8,6)(9,13)(10,17)(11,20)(12,19)(14,16)(15,23)(18,22)(21,24)(25,28)(26,32)(27,34)(29,36)(30,31)(33,38)(35,37)(39,40)(1,6,7,4)(2,8,5,3)(9,14)(10,11)(12,22)(13,16)(15,24)(17,20)(18,19)(21,23)(25,29)(26,33)(27,35)(28,36)(30,39)(31,40)(32,38)(34,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.