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