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