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