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