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