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