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