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