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