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