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