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