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