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