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