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