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