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