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