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