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