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