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