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