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