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