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