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