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