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