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)(11,17)(12,27)(13,29)(14,19)(15,31)(16,22)(18,21)(20,30)(23,36)(24,33)(25,38)(26,35)(28,39)(32,34)(37,40) involution — undirected(1,3,5,4)(2,6,8,7)(9,11,16,26)(10,17,22,35)(12,28,19,36)(13,24,30,40)(14,23,27,39)(15,32,18,25)(20,37,29,33)(21,38,31,34)(1,3,5,4)(2,7,8,6)(9,12,14,22,15,20,30,31,16,19,27,10,18,29,13,21)(11,17,24,36,25,34,39,37,26,35,40,28,32,38,23,33)(1,4,5,3)(2,7,8,6)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.