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