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