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