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