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