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