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