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