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