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