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