One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,7,5)(3,4,8,6)(11,17)(15,22)(18,20)(23,24)(25,26)(27,31)(28,32)(29,37)(30,34)(33,38)(35,36)(39,40)(2,5)(3,8)(9,10)(11,15)(12,19)(13,14)(16,21)(17,22)(18,24)(20,23)(25,27)(26,31)(28,34)(29,35)(30,32)(33,39)(36,37)(38,40) involution — undirected(1,3)(2,6)(4,5)(7,8)(10,14)(15,22)(16,19)(23,24)(25,26,30,34)(27,28,32,31)(29,37,38,33)(35,39,40,36)(1,4,7,6)(2,3,5,8)(9,11)(10,15)(12,20)(13,17)(14,22)(16,24)(18,21)(19,23)(25,27)(26,28)(29,35)(30,32)(31,34)(33,36)(37,39)(38,40)(1,5,7,2)(3,4,8,6)(9,12)(10,16)(11,18)(13,21)(14,19)(15,23)(17,20)(22,24)(25,28)(26,32)(27,34)(29,36)(30,31)(33,40)(35,37)(38,39)(1,6,7,4)(2,8,5,3)(9,10)(11,15)(12,16)(13,14)(17,22)(18,23)(19,21)(20,24)(25,29)(26,33)(27,35)(28,36)(30,38)(31,39)(32,40)(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.